Understanding the genetic basis of the physical and behavioural traits that
distinguish humans from other primates presents one of the great new challenges
in biology. Of the millions of base-pair differences between humans and
chimpanzees, which particular changes contributed to the evolution of human
features after the separation of the Pan and Homo lineages 5–7
million years ago? How can we identify the 'smoking guns' of human genetic
evolution from neutral ticks of the molecular evolutionary clock? The magnitude
and rate of morphological evolution in hominids suggests that many independent
and incremental developmental changes have occurred that, on the basis of recent
findings in model animals, are expected to be polygenic and regulatory in
nature. Comparative genomics, population genetics, gene-expression analyses and
medical genetics have begun to make complementary inroads into the complex
genetic architecture of human evolution.